Room temperature curing composition

ABSTRACT

A room temperature curing composition of this invention comprises an emulsion obtained by multi-stage emulsion polymerization of monomers, the emulsion comprising emulsion particles, a core of which comprises (A) 1 to 30% by weight of silyl group-containing vinyl monomer, (B) 70 to 99% by weight of vinyl monomer copolymerizable with component (A), the outermost shell of which comprises (A) 0.1 to 30% by weight of silyl group-containing vinyl monomer and (B) 40 to 99.4% by weight of vinyl monomer copolymerizable with component (A), and (D) 0.5 to 30% by weight of hydrophilic vinyl monomer. The room temperature curing composition of this invention has a stable silyl group, and a much improved film-forming ability after long-term storage and it also shows excellent mechanical stability, water-resistance, durability and white enamel gloss.

FIELD OF THE INVENTION

This invention relates to a room temperature curing composition forvarious coating systems, particularly for weather-resistant, durablecoatings, to be applied to outer surfaces of architectural structures,automobiles, household electric appliances, plastic products and so on.

BACKGROUND OF THE INVENTION

Recently, in the field of coatings and adhesives, organic solvent-basedsystems are being replaced with water-soluble or dispersible systems asan anti-pollution measure or resource saving.

However, the conventional water-based coatings have disadvantages inthat, since they have no crosslinkable functional group in themolecules, they are subject to the strong influence of surfactants usedin the polymerization, which remarkably deteriorate the weatherability,water resistance and stain resistance of formed coating films, resultingin inferior film performances as compared with solvent-based paints.

Therefore, to provide crosslinkable functional groups in the molecules,an application of an alkoxysilyl group-containing emulsion to the fieldof coatings has been proposed. However, the alkoxysilyl group is easilyhydrolyzed in the presence of water so that the film-forming performanceof the emulsion is deteriorated considerably after aging and, moreover,the emulsion is poor in mechanical stability and white enamel gloss.

SUMMARY OF THE INVENTION

As a result of making intensive studies in order to solve aboveproblems, inventors of the present invention have found that whenmulti-stage emulsion polymerization is performed, and polymerizablemonomers containing an alkoxysilyl group which is relatively stableagainst hydrolysis (e.g. triethoxysilyl group, diethoxysilyl group,tripropoxysilyl group, dipropoxysilyl group) are introduced to emulsionparticles as a reactive silyl group, the stability of the silyl groupsis remarkably enhanced so that the silyl groups are prevented fromhydrolysis in the course of polymerization or during storage.Additionally when hydrophilic groups are introduced into the outermostshell layer of the emulsion particles, the mechanical stability andwhite enamel gloss are both remarkably improved. This invention has beendeveloped on the basis of the above findings.

This invention is, therefore, directed to a room temperature curingcomposition comprising an emulsion obtained by a multi-stage emulsionpolymerization of the plurality of constituent monomers, wherein thecore monomer composition of emulsion particles comprises 1 to 30 weight% of (A) a silyl group-containing vinyl monomer of the general formula(I) and 70 to 99 weight % of (B) at least one vinyl monomercopolymerizable with the above-mentioned component (A), and the outershell monomer composition of the emulsion particles comprises 0.1 to 30weight % of (A) a silyl group-containing vinyl monomer of the generalformula (I), 40 to 99.4 weight % of (B) at least one vinyl monomercopolymerizable with the above-mentioned component (A) and 0.5 to 30weight % of (D) at least one hydrophilic vinyl monomer selected from thegroup consisting of α,β-ethylenically unsaturated carboxylic acid,styrenesulfonic acid, vinylsulfonic acid, sodium styrenesulfonate,2-sulfoethyl methacrylate sodium, 2-sulfoethyl methacrylate ammonium,(meth)acrylamide, N-methylol(meth)acrylamide, dialkylaminoalkylmethacrylates, dialkylaminoalkyl methacrylate hydrochlorides,2-aminoethyl methacrylate hydrochloride, polyethoxylated vinyl monomersand polypropoxylated vinyl monomers; ##STR1## wherein R is a monovalenthydrocarbon group, selected from alkyl group having 1 to 10 carbonatoms, aryl group and aralkyl group, X is a group selected from ethoxy,n-propoxy and i-propoxy groups, y is an integer of 0 to 2; in the casewhere two or more R or X groups are bound to Si respectively, they maybe the same or different.

The vinyl monomer (B) of the above-mentioned outermost shell preferablycomprises of 10 to 75 weight % of component (C) based on the totalmonomer amount of the outermost shell. The component (C) is at least onemonomer selected from alkyl methacrylates whose alkyl moieties containno fewer than 4 carbon atoms each and cycloalkyl methacrylates whosecycloalkyl moieties contain no fewer than 4 carbon atoms.

In the examples of component (D), (meth)acrylamide represents acrylamideor methacrylamide, N-methylol(meth)acrylamide representsN-methylolacrylamide or N-methylolmethacrylamide respectively,hereinafter referred to in the same manner.

DETAILED DESCRIPTION AND BEST MODE FOR PRACTICING THE INVENTION

The vinyl monomers (A), (B), (C) and (D) are now described in detailrespectively.

(A) Silyl group-containing vinyl monomer

The silyl group-containing monomer (A) of general formula (I) is notparticularly limited. As examples of the monomer (A), mentioned are thefollowing ##STR2##

The silyl group-containing vinyl monomers may be used alone or inadmixture thereof.

For the core, the silyl group-containing vinyl monomer (A) iscopolymerized in the proportion of 1 to 30% (by weight %; hereinafterthe same). When the proportion of monomer (A) for the core is less than1%, the water-resistance and durability tend to be deteriorated. Andwhen the proportion of monomer (A) is more than 30%, the emulsion tendsto be unstable, and gelation occurs during the polymerization of thecore. For the outermost shell, the silyl group-containing vinyl monomer(A) is copolymerized in the proportion of 0.1 to 30%. When theproportion of monomer (A) for the outermost shell is less than 0.1%, thedurability and water-resistance may be deteriorated due to the absenceof the crosslinking among particles. When the proportion of monomer (A)is more than 30%, the emulsion becomes unstable.

(B) Vinyl monomer copolymerizable with (A)

The vinyl monomer (B) copolymerizable with the above-mentioned monomer(A) is not limited to a particular species. As examples, mentioned are(meth)acrylate monomers, such as, methyl(meth)acrylate,ethyl(meth)acrylate, n-butylacrylate, iso-butylacrylate,tert-butylacrylate, benzyl(meth)acrylate, fluorine-containing vinylmonomers, such as, hexafluoropropyrene, chlorotrifluoroethylene,vinylidene fluoride, trifluoroethylene, tetrafluoroethylene,pentafluoropropyrene, trifluoro(meth)acrylate,pentafluoro(meth)acrylate, perfluorocyclohexyl(meth)acrylate,2,2,3,3-tetrafluoropropylmethacrylate,β-(perfluorooctyl)ethyl(meth)acrylate, aromatic hydrocarbon vinylmonomers such as styrene, α-methylstyrene, chlorostyrene,4-hydroxystyrene, vinyl-toluene, vinyl esters and allyl compounds suchas vinyl acetate, vinyl propionate, and diallyl phthalate, nitrilegroup-containing vinyl monomers such as (meth)acrylonitrile, epoxygroup-containing vinyl monomers such as glycidyl(meth)acrylate, hydroxygroup-containing vinyl monomer such as 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl(meth)acrylate, 2-hydroxyethyl vinyl ether,hydroxystyrene, Aronix 5700 (product of Toagosei Chemical industry Co.,Ltd.), Placcel FA-1, Placcel FA-4, Placcel FM-1, Placcel FM-4 (productsof Daicel Chemical Industries, Ltd.), HE-10, HE-20, HP-10, HP-20products of Japan Catalytic Chemical Industry Co., Ltd.), Blemmer PEPseries, Blemmer NKH-5050, Blemmer GLM (products of Nippon Oil & FatsCo., Ltd.), hydroxy-containing vinyl type modified hydroxyalkyl vinylmonomers, vinyl compounds which are a condensate of hydroxyalkyl estersof α,β-ethylenically unsaturated carboxylic acids, such as hydroxyalkylester of (meth)acrylic acid, with phosphoric acid or phosphoric acidester, urethane bond- or siloxane bond-containing (meth)acrylate vinylmonomer, macromonomer compounds such as AS-6, AN-6, AA-6, AB-6, AK-5,which are available from Toagosei Chemical industry Co., Ltd., vinylmethyl ether, vinyl chloride, vinylidene chloride, chloroprene,propylene, butadiene, other vinyl monomers, polymeric light stabilizersand polymeric ultraviolet absorbers such as LA87, LA82, LA22, which areavailable from Asahi Denka Kogyo Co., Ltd.

By using Fluorine-containing vinyl monomer or a siloxane containingvinyl monomer, the water repellency, water resistance and durability areimproved.

It is possible to generate crosslinking structure in the obtainedpolymer by using a monomer containing two or more polymerizableunsaturated bonds, such as polyethylene glycol dimethacrylate, ethyleneglycol diacrylate, triallyl cyanurate.

Component (B), including component (C) in the following descriptions,are polymerized 70 to 99% for the core, 40 to 99.4% for the outermostshell.

(C) Alkyl methacrylate whose alkyl moiety has no fewer than 4 carbonatoms and cycloalkyl methacrylate whose cycloalkyl moiety has no fewerthan 4 carbon atoms

Alkyl methacrylate whose alkyl moiety has no fewer than 4 carbon atomsand cycloalkyl methacrylate whose cycloalkyl moiety has no fewer than 4carbon atoms (C) are not particularly limited. As examples, mentionedare n-butylmethacrylate, iso-butylmethacrylate, tert-butylmethacrylate,2-ethylhexylmethacrylate, isodecylmethacrylate, laurylmethacrylate,tridecylmethacrylate, stearylmethacrylate, cyclohexylmethacrylate,isobornyl methacrylate. In the above mentioned examples,n-butylmethacrylate and cyclohexylmethacrylate are preferable from theviewpoints of cost performance, weatherability of the composition, thebalance between hardness and impact resistance and ease of control ofthe glass transition temperature (Tg) of the resin emulsion.

The proportion of component (C) to be copolymerized in the outermostshell of the multi-stage emulsion polymerization is preferably 10 to 75%based on all monomers of the outermost shell, more preferably 10 to 65%,and even more preferably 15 to 55%. When the proportion of component (C)is less than 10%, long-term storage stability may be deteriorated due tohydrolysis and condensation of silyl groups. When the proportion exceedsthe upper limit, mechanical stability tends to be deteriorated due toincreasing hydrophobicity of the outermost shell of the particles.

The component (C) may be used in the core emulsion polymerization. Whenthe proportion of component (C) is too large, however, the gloss of theformed film and mechanical stability of the paint tend to bedeteriorated. Thus the proportion of component (C) is not more than 75%of all monomers used in the core, preferably not more than 65%, morepreferably not more than 55% and even more preferably not more than 40%.

(D) Hydrophilic vinyl monomer

The outermost shell of the emulsion particles must contain thehydrophilic vinyl monomer (D), which is selected from α, β-ethylenicallyunsaturated carboxylic acids, styrenesulfonic acid, vinylsulfonic acid,sodium styrensulfonate, 2-sulfoethyl methacrylate sodium, 2-sulfoethylmethacrylate ammonium, (meth)acrylamide, N-methylol(meth)acrylamide,dialkylaminoalkyl methacrylates, dialkylaminoalkyl methacrylatehydrochlorides, 2-aminoethyl methacrylate hydrochloride, polyoxyethylenechain-containing vinyl monomers and polyoxypropylene chain-containingvinyl monomers.

As examples of α,β-ethylenically unsaturated carboxylic acids, mentionedare (meth)acrylic acid, maleic acid, itaconic acid, crotonic acid,fumaric acid, citraconic acid.

As examples of dialkylaminoalkyl methacrylates and dialkylaminoalkylmethacrylate hydrochlorides, mentioned are dimethylaminoethylmethacrylate, diethylaminoethyl methacrylate, dimethylaminopropylmethacrylate and its hydrochlorides.

Polyoxyethylene chain-containing vinyl monomers are not particularlylimited, but polyoxyethylene chain-containing (meth)acrylic esters arepreferred. As examples, mentioned are Blemmer PE-90, PE-200, PE-350,PME-100, PME-200, PME-400, AE-350 (products of Nippon Oil and Fats Co.,Ltd.), MA-30, MA-50, MA-100, MA-150, RA-1120, RA-2614, RMA-564, RMA-568,RMA-1114, and MPG130-MA (products of Nippon Nyukazai Co., Ltd.).

Polyoxypropyrene chain-containing vinyl monomers are not particularlylimited. As examples, mentioned are Blemmer PP-1000, PP-500, PP-800,AP-400 products of Nippon Oil and Fats Co., Ltd.), and RS-30 products ofSanyo Chemical Industries, Ltd.).

The silyl group stability is improved remarkably by usingpolyoxyethylenyl vinyl monomers as the component (D), and consequentlyfilm-forming performance is not deteriorated, and mechanical stabilityand white enamel gloss are satisfied. The number of oxyethylene units inthe polyoxyethylene chain is preferably 2 to 30. If it is less than 2,the mechanical stability and white enamel gloss is deteriorated. If itexceeds 30, the coating film tends to be softened and pick up dirteasily.

The component (D) is copolymerized in the proportion of 0.5 to 30%. Ifthe proportion is less than 0.5%, some properties, such as mechanicalstability and white enamel gloss are compromised. If it is more than30%, the water-resistance is decreased.

The process for production of the emulsion is described in the followingsection.

As the first stage of polymerization, a mixture of component (A) and (B)is polymerized by a known emulsion polymerization method, and the secondand subsequent stages of polymerization are serially carried out in thepresence of the obtained polymer (referred to at the core). The monomercomposition can be the same or different between the second andsubsequent stages of polymerization and the first stage. And the polymerobtained in the last stage of the polymerization is called the outermostshell. In this invention, the outermost shell must contain the component(D) in the proportion of 0.5 to 30%.

The multi-stage polymerization of this invention is conducted in 2 to 4stages, and it is preferable to polymerize in the manner that the weightratio of the core to the other part is in the range of 10:90 to 90:10.In this invention, the polymer obtained in the above-mentioned manner iscalled a multilamellar polymer.

By using polyoxyethylenyl anionic surfactant as the surfactant in thepolymerization system, the silyl group is stabilized. As the examples ofthe anionic surfactant, mentioned are polyoxyethylenenonylphenyl ethersulfate such as Newcol-560SN, Newcol-560SF (products of Nippon NyukazaiCo., Ltd.), Emal NC-35, and Level WZ (products of Kao corporation),polyoxyethyleneallyl ether sulfate, such as, Newcol-707SF, Newcol-707SN,Newcol-723SF, and Newcol-740SF, octylphenoxyethoxyethylsulfonate, suchas, Newcol-861SE, and polyoxyethylene-tridecyl ether sulfate, such as,Newcol-1305SN (products of Nippon Nyukazai Co., Ltd.).

The number of oxyethylene units in the polyoxyethylene chain ispreferably 1 to 50 to stabilize the polymerization reaction andhydrolyzable silyl groups. Also an anionic surfactant of ammonium saltis preferred from the viewpoint of water resistance of the coating filmobtained from the emulsion.

Polyoxyethylene chain-containing anionic surfactant can be used incombination with other ionic or nonionic surfactants.

The other ionic surfactants are not particularly limited. As examples ofthe surfactants, mentioned are salts of sulfonic acid, such as, sodiumlaurylsulfonate, sodium dodecylbenzenesulfonate, sodium isooctylbenzenesulfonate.

The nonionic surfactant is not particularly limited. As examples of thesurfactant, mentioned are polyoxyethylene compounds, such aspolyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, andsilicon-containing nonionic surfactants such as L-77, L-720, L-5410,L-7602 and L-7607 (products of Union Carbide Co.)

The use of a reactive surfactant containing a polymerizable double bondwithin a molecule is also permitted in this invention. Especially byusing a reactive surfactant containing a polyoxyethylene group within amolecule, the water resistance is improved. Also the reactive surfactantcan be used only in the outermost shell. As examples of such surfactant,mentioned are Adekariasoap NE-10, NE-20, NE-30, NE-40 and SE-10N(products of Asahi Denka Kogyo K.K.), Antox-MS-60 (product of NipponNyukazai Co., Ltd.), Aqualon RN-20, RN-30, RN-50, HS-10, HS-20 and,HS-1025 (products of Daiichi Kogyo Seiyaku Co., Ltd.).

The proportion of the polyoxyethylene chain-containing anionicsurfactant based on the total monomer weight is 0.01 to 20% andpreferably 0.05 to 10%. If the proportion is less than 0.01%, stabilityduring the polymerization reaction is decreased, and if the proportionis more than 20%, the water-resistance is decreased.

Also, a water-soluble resin can be used additionally in thepolymerization system. By using this method, water-resistance of thecoating film is improved. By introducing silyl groups of general formula(I) into the water-soluble resin, the water-resistance can be moreimproved.

To insure a more stable polymerization, the reaction is carried out inthe presence of a redox catalyst at a temperature not more than 70 andpreferably 40 to 65° C. To stabilize the silyl groups, pH of theemulsion is preferably adjusted to 5 to 8 during the polymerizationreaction, and more preferably 6 to 7.

As examples of the above-mentioned redox catalyst, there may bementioned such combination as potassium persulfate or ammoniumpersulfate with acid sodium sulfite or Rongalit, hydrogen peroxide withascorbic acid, and an organic peroxide such as t-butyl hydroperoxide,benzoyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide or thelike with acid sodium sulfite or Rongalit. Especially the combination ofan organic peroxide with a reducing agent is preferable for stabilizingpolymerization. And in order to get catalyst activity constantly, aferrous ion-containing compound such as ion sulfate and a chelatingagent such as salt of ethylenediaminetetraacetate like disodiumethylenediaminetetraacetate can be used additively.

The proportion of said redox catalyst (initiator) is preferably 0.01 to10% based on the total monomer weight, and more preferably 0.05 to 5%.

It is also possible to add a chain transfer agent to control themolecular weight of the polymer obtained from the polymerization.

As examples of the chain transfer agent, mentioned are mercaptans,sulfidebenzenes, isopropylbenzenes, chloroform, carbon tetrachloride,ferric chloride. Especially among the mercaptans, n-dodecylmercaptan,t-dodecylmercaptan, n-butylmercaptan, γ-mercaptopropyltrimethoxysilane,γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane,and γ-mercaptopropylmethyldiethoxysilane are preferable from the viewpoints of cost, odor and efficiency.

In the case of using the chain transfer agent, the preferable proportionis 0.01 to 10%. When the proportion is less than 0.01%, molecular weightcontrolling ability is decreased. When the proportion is more than 10%,water-resistance and durability will be decreased.

In this invention, the solid content of the emulsion is preferably 20 to70%, and more preferably 30 to 60%. When the solid content is more than70%, removing heat generated by polymerization reaction becomesdifficult due to the marked rise of the viscosity of the system, and ittakes a long time to remove the emulsion from the polymerization vessel.When the solid content is less than 20%, the operation problem does notoccur. However, the amount of resin produced by one polymerizationoperation is small, and it is very disadvantageous in an economicalpoint of view. Moreover, when applying the obtained composition topaint, the solid content below 20% makes the formed film thinner, andconsequently some problems, such as, deterioration of film performancesor of workability are caused. For instance, it is required to increaserepeat time of painting to obtain desired thickness.

The obtained emulsion is composed of ultra fine particles having anaverage particle size of about 0.02 to 1.0 μm, thus having an excellentfilm forming ability.

Also by adding a curing agent to the composition of this invention justbefore painting, the crosslinking is accelerated. As the curing agent,organic metal compounds, acid catalysts and basic catalysts can be used.From the viewpoint of catalyst activity, organoaluminium compounds,organotin compounds and mixtures or reaction products of phosphoric acidester and amine are preferable.

As examples of the organic metal compound, mentioned are organotincompounds such as dibutyl tin dilaurate, dibutyl tin dimaleate, dioctyltin dilaurate, dibutyl tin diacetate, dibutyl tin dimethoxide, tributyltin sulfite, dibutyl tin thio glycolate, dioctyltin, organoaluminiumcompounds such as aluminum isopropylate,aluminumtris(ethylacetoacetate), aluminumtris(acetylacetonate),ethylacetoacetate aluminum diisopropylate.

To retain catalyst activity and to get good storage stability, it ispreferable that these organic tin compounds are previously emulsified bya surface active agent comprised of mainly an alkyl ether type agent andadded to the composition just before using. The amount of the organicmetal compound is preferably 0.01 to 10 parts by weight per 100 parts(parts by weight; hereinafter the same) of the solid content of silylgroup-containing emulsion, and more preferably 0.1 to 5 parts.

As examples of mixtures or reactants of a phosphoric acid ester andamine are monobutyl phosphate, dibutyl phosphate, isopropylacidphosphate, di-2-ethylhexyl phosphate. And as examples of the amine,mentioned are hexylamine, triethylamine, N,N-dimethyldodecylamine,3-propanolamine. The proportion of these mixtures or reactants ispreferably 0.001 to 10 parts per 100 parts of the solid content of silylgroup-containing emulsion and more preferably 0.01 to 5 parts. When theproportion of the curing agent is below 0.01 part, the catalyst activityis decreased, and when the proportion is more than 10 parts, thewater-resistance is decreased.

Pigments usually used in paints (white pigments such as titaniumdioxide, calcium carbonate, barium carbonate or kaoline, and colorpigments such as carbon black, colcothar, phthalocyanine blue) can beadded to the thus obtained curing composition. Titanium dioxide is themost popular and important among the pigments.

By using titanium dioxide surface-modified by alumina and/or zirconia,the gloss and weatherability are improved.

Additives which have been employed as usual paint components can beadded in the composition, such as film-foaming agents, colloidal silica,plasticizers, solvents, dispersants, thickeners or thixotropic agents,antifoams, preservatives, or ultraviolet absorbers.

And for attaining fast curing, a silane coupling agent, a melamine resinor an isocianate compound can be employed as a crosslinking agent.

The composition of this invention can be applied to clear coating filmor to an opaque coating film containing pigments. For example, thecomposition is used as coating or finishing materials for the interiorof architectural structures, automobile uses such as metallic basecoating or clear coating on the metallic base, direct coating ontometal, such as, aluminum and stainless steel, direct coating onto othermaterials, such as, slate, concrete, roofing tile, mortar, gypsum board,asbestos cement slate, asbestos board, precast concrete, light-weightcellular concrete, calcium silicate board, tile, brick and otherceramics, coating onto stone articles and other materials such as glass,natural marble, granite or as a surface modifier. The composition ofthis invention can be used not only for direct coating of materials, butalso for coating on a water-based or solvent based primer, an acrylicrubber, a multi-layer top coat, a water-based or solvent-basedpenetrative water absorption inhibitor coat on an inorganic materialsuch as concrete. And the composition can be used as adhesives andtackifiers.

Moreover, the composition can be blended with commercial aqueous coatingmaterials, for example, thermosetting acrylic coatings, such as, acrylicor acrylmelamine resin coatings, alkyd, epoxy, fluororesin coatings,which can improve its weatherability, acid-resistance andsolvent-resistance.

EXAMPLES

The following examples further illustrate the composition of the presentinvention and the method of preparing or producing the same. However,this invention is not limited to the range of examples.

Examples 1 to 10, Comparative Examples 1 to 6

A reactor equipped with a reflux condenser, a tube for introducingnitrogen gas and dropping funnel and stirrer was charged with 120 partsof deionized water, 0.7 parts of rongalit, 3 parts of NEWCOL-707SF, 0.6parts of ammonium acetate, 0.7 parts of t-butyl hydroperoxide and amonomer mixture having the composition shown in Table 1. The chargedmixture was heated to 50° C. with nitrogen gas and polymerization wascarried out. After polymerizing for 1 hour, in Examples 1 to 8, 10 andComparative Examples 1 to 6, 0.3 parts of t-butyl hydroperoxide and amonomer emulsion having the composition shown in Table 2 were addeddropwise to the reactor for 3 hours.

Example 9 represents three-stage polymerization processes. After 1 hourpolymerization of a monomer emulsion of the core shown in Table 1, thesecond stage monomer emulsion shown in Table 2 (the left column ofexample 9) and 0.2 parts of t-butyl hydroperoxide were added dropwise tothe reactor for 2 hours, and the monomer emulsion of the outermost shell(the right column of example 9 in Table 2) and 0.1 part of t-butylhydroperoxide was added dropwise for 1 hour.

Additional polymerization was conducted for 1 hour after the completionof the dropwise addition, and the obtained emulsion was adjusted to pH 7by using aqueous ammonia, and was adjusted to 40% of solid content byusing deionized water.

The obtained emulsion was evaluated with the following method. Theresults are shown in Table 3.

Evaluation Method

(1) Polymerization Result (Stability during the Polymerization)

After the completion of polymerization, the emulsion was filteredthrough 200 mesh, and the weight of scale left on the mesh was measured.In the case that the scale amount is not more than 0.5% by weight basedon total resin weight, a mark `◯` is shown in Table 3.

(2) Long-Term Storage Stability (Appearance)

The obtained emulsion was stored for 1 and 3 months at 50° C.respectively, then the appearance of the emulsion was observed visually.

(3) Long-Term Storage Stability (5° C. Film-Forming Ability)

After storing for 1 and 3 months at 50° C. respectively, 10 parts ofCS12 (a film-forming agent produced by Chisso corporation) was added per100 parts of emulsion (solid basis) and left overnight at 5° C. Then aglass plate was coated with the emulsion and kept overnight at 5° C.,and the surface appearance was observed.

◯: no cracking occurs

Δ: fine cracking occurs in part

x: cracking occurs all over the surface

(4) Mechanical Stability

According to JIS K 6392, the test was carried out using 10 Marlon testerat a load of 15 kg for 5 minutes. After the loading, the weight of theformed aggregate was measured and its proportion (ppm) to the solidcontent of the charged emulsion was calculated.

(5) White Enamel Gloss

The composition was mixed according to the recipe shown below anddispersed by using a sand mill for 1 hour by 1000 rpm to obtain apigment paste. To 30 parts of the pigment paste, 60 parts of theemulsion, 2.4 parts of CS12, 3 parts of propylene glycol, 0.02 part ofSN defoamer381, 4 parts of 20% UH420 (a thickener produced by AsahiDenka Kogyo Co., Ltd.) and 2.0 parts of 2% Thilose H4000P were added andthe mixture was stirred to obtain white enamel coatings. Tin compoundsemulsified according to Recipe 1 were added to the white enamel coatingpaints, and the paints were coated on glass plates. After leaving themfor 1 day at room temperature and for 3 months at 50° C., 60 degreegloss was measured with a glossmeter.

    ______________________________________                                        Pigment paste recipe                                                          water                      16.5   parts                                       14% aqueous ammonium       0.3    parts                                       Laymal SMA1440H (a pigment wetting agent produced                                                        4      parts                                       by ATOCHEM Corporation)                                                       EmalgenA-60 (a pigment wetting agent produced by Kao                                                     0.7    parts                                       Corporation)                                                                  SNdefoamer381 (a defoaming agent produced by San                                                         0.3    parts                                       Nopco Co., Ltd.)                                                              2% Thilose H4000P (a thickening agent produced by                                                        6.5    parts                                       Hoechst Japan)                                                                Titanium dioxide (a pigment)                                                                             72     parts                                       Recipe 1                                                                      Dibutyltin dilaurate       10     parts                                       TD-10014 (a surfactant produced by Nippon Nyukazai Co.,                                                  4      parts                                       Ltd.)                                                                         TD-1006 (a surfactant produced by Nippon Nyukazai Co.,                                                   6      parts                                       Ltd.)                                                                         propylene glycol           10     parts                                       deionized water            70     parts                                       ______________________________________                                    

(6) Water Resistance

In Examples 1 to 8, 10 and Comparative Examples 1 to 6, 0.4 gram of CS12and 0.04 gram (solid content) of tin compound emulsified by homogenizerwere added to 10 grams of the emulsion, and mixed together. In Example9, 0.4 gram of CS12 and 0.4 gram of the solution shown in recipe 2 belowwere added to 10 grams of the emulsion, and mixed together. The mixturewas coated onto the polyethylene sheet, and dried for 10 days at roomtemperature, then it was immersed in water for a day at roomtemperature. The water-resistance was measured by the proportion ofincreased weight to the weight of the film before immersion.

    ______________________________________                                        Recipe 2                                                                      ______________________________________                                        MP4 (a monobutyl phosphate produced by Daihati Kagaku                                                      5 parts                                          Kogyo, Co., Ltd.)                                                             3-aminopropanol              5 parts                                          deionized water             90 parts                                          ______________________________________                                    

                                      TABLE 1                                     __________________________________________________________________________    Core monomer                                                                           Example             Comparative example                              composition (parts)                                                                    1 2 3 4 5 6 7 8 9 10                                                                              1 2 3 4 5 6                                      __________________________________________________________________________    Methyl methacrylate                                                                    50                                                                              50                                                                              50                                                                              40                                                                              50                                                                              50                                                                              50                                                                              50                                                                              50                                                                              50                                                                              50                                                                              55                                                                              45                                                                              15                                                                              15                                                                              13                                     Butyl acrylate                                                                         40                                                                              40                                                                              40                                                                              30                                                                              40                                                                              40                                                                              40                                                                              40                                                                              40                                                                              40                                                                              40                                                                              45                                                                              40                                                                              15                                                                              15                                                                              12                                     Butyl methacrylate                                                                     --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              65                                                                              65                                                                              65                                     γ-methacryloxy                                                                   --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              5 5 5 --                                     propyl                                                                        trimethoxysilane                                                              γ-methacryloxy                                                                   10                                                                              --                                                                              --                                                                              20                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                     propyl                                                                        triethoxysilane                                                               Vinyltriethoxysilane                                                                   --                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                     γ-methacryloxy                                                                   --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                     propyl tri-i-                                                                 propoxysilane                                                                 __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Monomer emulsion                                                              composition of the                                                            second stage and the                                                          outermost shell                                                                        Example                          Comparative example                 (parts)  1  2  3  4  5  6  7  8  9     10 1  2   3  4   5  6                  __________________________________________________________________________    Methyl methacrylate                                                                    38 38 38 33 26 28 38 38 24 14 46 40 40  40 13  10 10                 Butyl acrylate                                                                         28 28 28 23 20 28 28 28 18 10 35 30 36  31 13  11 11                 Butyl methacrylate                                                                     20 20 20 20 40 20 20 20 12 8  5  20 20  20 65  65 65                 Styrene  -- -- -- -- -- 10 -- -- -- -- -- -- --  -- --  -- --                 γ-methacryloxy                                                                   -- -- -- -- -- -- -- -- -- -- -- -- --  5  5   -- --                 propyl                                                                        trimethoxysilane                                                              γ-methacryloxy                                                                   10 -- -- 20 10 10 10 10 6  4  10 10 --  -- --  10 10                 propyl                                                                        triethoxysilane                                                               Vinyltriethoxysilane                                                                   -- 10 -- -- -- -- -- -- -- -- -- -- --  -- --  -- --                 γ-methacryloxy                                                                   -- -- 10 -- -- -- -- -- -- -- -- -- --  -- --  -- --                 propyl tri-i-                                                                 propoxysilane                                                                 MA-50*1  4  4  4  4  4  4  4  4  -- 4  4  -- 4   4  4   4  4                  Water    60 60 60 60 60 60 60 60 36 24 60 60 60  60 60  60 60                 N-707SF*2                                                                              1.6                                                                              1.6                                                                              1.6                                                                              1.6                                                                              1.6                                                                              1.6                                                                              -- -- 1.0                                                                              0.6                                                                              1.6                                                                              1.6                                                                              1.6 1.6                                                                              1.6 1.6                                                                              1.6                Sodium   -- -- -- -- -- -- 1.6                                                                              -- -- -- -- -- --  -- --  -- --                 dodecylbenzene                                                                sulfonate                                                                     HS-10*3  -- -- -- -- -- -- -- 1.6                                                                              -- -- -- -- --  -- --  -- --                 __________________________________________________________________________     *1MA-50: a hydrophilic vinyl monomer containing polyoxyethylene chain         (produced by Nippon Nyukazai Co., Ltd.)                                       2N707SF: an anionic surfactant containing polyoxyethylene chain (produced     by Nippon Nyukazai Co, Ltd.)                                                  3HS10: a reactive surfactant (produced by Daiichi Kogyo Seiyaku Co., Ltd.

                                      TABLE 3                                     __________________________________________________________________________                Example             Comparative example                           Results of evaluation                                                                     1 2 3 4 5 6 7 8 9 10                                                                              1   2 3 4 5 6                                 __________________________________________________________________________    polymerization results                                                                    ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                     ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                     Storage                                                                            Appearance                                                                           ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                     ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                     stability                                                                          Film-forming                                                                         ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                     ◯                                                                   X ◯                                                                   ◯                                                                   ◯                     (1 month)                                                                          ability (5° C.)                                                   Storage                                                                            Appearance                                                                           ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                     ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                     stability                                                                          Film-forming                                                                         ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                   ◯                                                                     ◯                                                                   X X X ◯                     (3 months)                                                                         ability (5° C.)                                                   White enamel gloss                                                                        80                                                                              80                                                                              80                                                                              75                                                                              75                                                                              80                                                                              80                                                                              75                                                                              80                                                                              75                                                                              20  80                                                                              80                                                                              75                                                                              75                                                                              70                                White enamel gloss after                                                                  80                                                                              80                                                                              80                                                                              75                                                                              70                                                                              75                                                                              80                                                                              75                                                                              75                                                                              &0                                                                              20  75                                                                              15                                                                              15                                                                              20                                                                              70                                storage (50° C. × 3 months)                                      Mechanical property (ppm)                                                                 25                                                                              20                                                                              25                                                                              10                                                                              30                                                                              25                                                                              20                                                                              15                                                                              20                                                                              20                                                                              25000                                                                             50                                                                              20                                                                              60                                                                              60                                                                              50                                Water resistance (%)                                                                      7 10                                                                              7 5 7 7 9 8 6 10                                                                              8   90                                                                              7 7 8 8                                 __________________________________________________________________________

INDUSTRIAL APPLICABILITY

The room temperature curing composition of this invention has a stablesilyl group and a much improved film-forming ability after long-termstorage. Also the composition shows excellent mechanical stability,water-resistance, durability and white enamel gloss. Thus thecomposition can be widely applied to the surfaces of architecturalstructures, automobiles, household electric appliances, plastic productsand so on.

We claim:
 1. A room temperature curing composition obtained frommultistage emulsion polymerization of a monomer composition whichcomprises a core monomer composition comprising 1 to 30% by weight of(A) vinyl monomer containing silyl group of general formula (I) shownbelow and 70 to 99% by weight of (B) vinyl monomer copolymerizable withcomponent (A), (B), as a component of the monomer composition in thecore, comprising 0 to 55% by weight of component (C) based on the totalmonomer amount of the core, component (C) being at least one monomerselected from alkylmethacrylate containing alkyl group which has nofewer than 4 carbon atoms, and cycloalkylmethacrylate containingcycloalkyl group which has no fewer than 4 carbon atoms, and anoutermost shell monomer composition comprising 0.1 to 30% by weight of(A) vinyl monomer containing silyl group of formula (I) shown below, 40to 99.4% by weight of (B) vinyl monomer copolymerizable with component(A), 0.5 to 30% by weight of (D) at least one hydrophilic vinyl monomerselected from α,β-ethylenically unsaturated carboxylic acid,styrenesulfonic acid, vinylsulfonic acid, sodium styrene sulfonic acid,2-sulfoethylmethacrylate sodium, 2-sulfoethylmethacrylate ammonium,(meth)acrylamide, N-methylol(meth)acrylamide, dialkylaminoalkylmethacrylate, dialkylaminoalkyl methacrylate hydrochlorides,2-aminoethyl methacrylate hydrochlorides, polyoxyethylenechain-containing vinyl monomers or polyoxypropylene chain-containingvinyl monomers, and as a part of (B) component in monomer composition ofthe outermost shell, 15 to 55% by weight of component (C) is containedbased on the total monomer amount of the outermost shell, said component(C) being at least one monomer selected from alkylmethacrylatecontaining alkyl group which has no fewer than 4 carbon atoms, andcycloalkylmethacrylate containing cycloalkyl group which has no fewerthan 4 carbon atoms; ##STR3## wherein R represents a monovalenthydrocarbon group selected from alkyl group containing 1 to 10 carbonatoms, aryl group or aralkyl group; X represents a group selected fromethoxy, n-propoxy or iso-propoxy, y represents an integer of 0 to 2;when two or more X and R groups bound to Si respectively, they may bethe same or different.
 2. The room temperature curing composition asclaimed in claim 1, wherein said hydrophilic vinyl monomer (D) is avinyl monomer containing polyoxyethylene chain and said emulsion isobtained by copolymerization using an anionic surfactant containingpolyoxyethylene chain.
 3. The room temperature curing composition asclaimed in any one of claims 1 or 2, wherein a reactive surfactantcontaining polyoxyethylene chain is used in the polymerization.
 4. Theroom temperature curing composition as claimed in any one of claims 1 or2, further comprising a curing agent.
 5. The room temperature curingcomposition as claimed in claim 4, wherein the curing agent is anorganoaluminum compound or an organotin compound emulsified by a surfaceactive agent mainly comprised of an alkyl ether agent.
 6. The roomtemperature curing composition as claimed in claim 4, wherein the curingagent is a mixture or a reaction product of phosphoric acid ester andamine.